Shopify main-thread CPU breakdown and the Core Web Vitals

Sites with 150 to 450ms of scripting CPU main-thread CPU breakdown have a good INP most often: 100%, against 99% of all Shopify sites. Sites with under 150ms of scripting CPU scripting CPU have it least often, at 98%.

Over 1,200ms of scripting CPU is the most used: 45.8% of Shopify sites. 150 to 450ms of scripting CPU is 17.9% of Shopify sites.

On jQuery, 52% of sites use over 1,200ms of scripting CPU main-thread CPU breakdown, and 99% of jQuery sites have a good INP, against 99% of all sites. On Vue, 61% of sites use over 1,200ms of scripting CPU, and 100% of Vue sites have a good INP.

FrameworkMain-thread CPU breakdown on its sitesGood INP

All Shopify sites 8,246 sitesOver 1,200ms scripting CPU 46%450 to 1,200ms scripting CPU 32%150 to 450ms scripting CPU 18%99%

Vue 933 sitesOver 1,200ms scripting CPU 61%450 to 1,200ms scripting CPU 27%100%

jQuery 3,153 sitesOver 1,200ms scripting CPU 52%450 to 1,200ms scripting CPU 31%150 to 450ms scripting CPU 13%99%

Over 1,200ms scripting CPU 450 to 1,200ms scripting CPU 150 to 450ms scripting CPU Under 150ms scripting CPU

Does the framework explain the main-thread CPU breakdown difference?

On jQuery, 100% of sites with 150 to 450ms of scripting CPU main-thread CPU breakdown have a good INP, against 99% of jQuery sites with over 1,200ms of scripting CPU. Within jQuery, sites with 150 to 450ms of scripting CPU and over 1,200ms of scripting CPU have a good INP about equally often. On Vue, 100% of sites with over 1,200ms of scripting CPU main-thread CPU breakdown have a good INP, against 100% of Vue sites with 450 to 1,200ms of scripting CPU. Within Vue, sites with over 1,200ms of scripting CPU and 450 to 1,200ms of scripting CPU have a good INP about equally often.

Why scripting dominates main-thread CPU budgets

Across the web, JavaScript evaluation accounts for the largest share of total main-thread CPU time, dwarfing HTML parsing, style calculation, and painting. Across 1,472 sites (17.9%) spending 150 to 450ms in scripting CPU, 100% pass field INP (42ms median), while the 45.8% (3,779) exceeding 1,200ms drop to 99% good INP (66ms median).